National Geographic explorer and storm researcher Tim Samaras set out to document tornadoes and lightning on a trip through Oklahoma. But a destructive hailstorm with some hailstones nearly softball-size was a surprise highlight of this day in the field. Joining Samaras on this day were photographer Carl Young and National Geographic photographer Carsten Peter.

NARRATION: \u00a0Severe-storms researcher Tim Samaras went into the field this spring to document lightning and tornadoes for National Geographic.

NARRATION: \u00a0But sometimes, the unexpected happens, and with cameras rolling on this day near Watonga, and Kingfisher, Oklahoma, Tim and his team found themselves in the midst of a destructive hailstorm.

SOT: Aw! There goes the windshield!

NARRATION: \u00a0But, this wasn't the worst of it.

TIM SAMARAS: \"Very strong inflow.\"

NARRATION: \u00a0A strong updraft is one of the main ingredients of a hailstorm.

SOT: \"Did you see that?

TIM SAMARAS: \"There they are.\u00a0 I got them. \u00a0That was a huge hailstone. This is the real thing.\"

SOT: \"That will kill somebody!\"

CARTSEN PETER: \"That's amazing.\"

TIM SARAMAS: \"I'm not so sure....\u00a0 There's another one falling. I don't know, man.\u00a0 It's probably not safe to be out here.\"

CARL YOUNG: \"Oh! It's coming!\u00a0 It's starting to come in now.\u00a0\u00a0 Let's get out of here!\"

CARL YOUNG: \"My window's already broken, but I don't want the side windows to break.\"

NARRATION: \u00a0Baseball and softball sized hailstones falling by the thousands.

TIM SARAMAS:\u00a0 \"That is beautiful! Look at that!\"

NARRATION: \u00a0Tim measured the biggest they collected at 4 inches... nearly the size of a softball.\u00a0\u00a0\u00a0 Any hail larger than one inch in diameter triggers a severe storm warning by the National Weather service, damaging to crops, people and animals and car windshields.

SOT: Oh!

NARRATION: \u00a0Tim Samaras and his team will head back into the field in search of tornadoes, lightning... and maybe even another big hailstorm.